The present invention relates to a fastening device and assembly for establishing a fastening connection between a container and a ship and to a method of establishing a fastening connection between a container and a ship.
Shipping is an example of an area in which fixation and retaining of objects is very relevant. Especially, as transportation by ship usually requires more substantial fixation in order to retain the objects in place e.g. during frequently changing weather conditions. Various methods and devices have been suggested in order to secure the objects, such as containerized cargo, to the deck of a ship e.g. a containership.
FIGS. 1a and 1b illustrate a common example of a modern containership seen from above and from the side, respectively. The containership comprises a number of containers located on the ship deck as well as below deck (not illustrated on the figures). To facilitate the carriage of a significant amount of containers the containers are closely stacked on deck in a height of several containers e.g. four containers on top of each other and four columns of containers across the ship deck as illustrated in FIG. 2a. 
Once the containership is at sea, the containership's pitching, yawing and particularly its rolling affects the container stacks. Especially, if the containership encounters heavy weather, it may experience rolls of as much as 30 degrees from vertical. The rolling of the containership requires that the fixation is continuously adjusted in order to keep it tight and thus the containers secure on deck.
FIG. 2a further illustrates that space may be present between the top and bottom of the stacked containers e.g. due to pebbles, dirt or local unevenness of the containers. Upon the influence of the load, the ship's pitching, yawing and rolling motion and vibrations, the pebbles, dirt etc. may give way and the containers move closer together after some time, and thus the fixation needs to be readjusted to keep it tight.
FIG. 2b illustrates a well-known system of fixating and lashing containers to the deck or the hatch cover of a containership. The system comprises rods set up in traverse patterns over the faces of the containers and when containers are stacked, e.g. four or more high, double-height crosses that span two layers are superimposed on a bottom row of single-height crosses. The containers are also held together with twistlocks engaging with the top and bottom corners of containers positioned on top of each other. The twistlocks ensure that the upper container layers, which are not lashed by the system, stay in place.
A turnbuckle is provided for each rod to provide a manually adjustable connection to the deck of the ship. The tightening of the rods is performed from deck level by a ship worker or assistant equipped with a turnbuckle spanner or a similar handling tool.
The spanner is used to engage and turn the body of the turnbuckle in a left or right direction, whereby the left and the right screw threaded rod ends in the turnbuckle are turned closer or further apart.
A modern containership often carries thousands of containers on deck. A problem is the lashing of the deck containers since it involves numerous turnbuckles which all must be tightened during loading at port, frequently at sea in order to secure the container cargo from going overboard and releasing during unloading at port. The turnbuckles often weigh between 10 and 25 kilograms. The workers thus carry a significant weight load at the lashing. After establishment of the lashing the workers are facing the demanding task of tightening the thousands of turnbuckles with turnbuckle spanners. The tightening of the turnbuckles must be performed in all kinds of weather and often under very cramped conditions, as the containers are stacked very close to each other.
The tightening of the turnbuckles requires much man power and is obviously very time consuming, which is especially disadvantageous at port as many efforts have been made by the owners of the containerships to minimize the time the ships are at port. The lashing is thus very costly in time and money for the companies that operate the containerships.